1. Field of the Invention
This invention relates to methods of and apparatus for drilling bores in the earth to tap deposits of materials such as petroleum and natural gas. More particularly, the instant invention relates to methods of and apparatus for inhole drilling, wherein a torque arrestor is utilized to prevent rotation of an inhole drill assembly so as to improve both vertical well-drilling techniques and horizontal boring techniques.
2. Prior Art and Technical Considerations
The usual method for drilling oil and gas wells is to attach a bit to a "string" of pipes and to rotate the pipes via a surface drive. The bits depend on the "string" weight and surface drive torque to produce a scraping or grinding action as it is rotated at the bottom of the bore hole. This requires considerable torque and generates enormous pressure on the drill bit. To change a bit, the "string" must be removed from the bore hole. This is an expensive, complex, time-consuming and dangerous procedure. The pipes are connected to the drill bit in sections to form the "string". This is an expensive, complex, unreliable and dangerous procedure. Frequently, the string is a couple of thousand feet long. During the drilling operation, pipe sections can break, which necessitates retrieving that portion of the string which extends from the surface down to the break and then reassembling the string.
In addition, by utilizing the aforedescribed drilling procedure, it is virtually impossible to drill in a horizontal direction. Consequently, oil and gas deposits which are distributed in horizontal strata (sometimes less than ten feet in thickness) can really only be punctured using the conventional approach. The "puncture" can be expanded by various methods; however, one cannot conveniently bore laterally of the initial vertical well hole to access directly lateral areas of the field. Consequently, in order to effectively pump out a field, numerous vertical wells, which are fairly close to one another, must be drilled.
One approach to solving this problem is to utilize an inhole drill assembly wherein the pipe string is not necessary, since the drill is powered by an air motor, or perhaps electric motor, which is proximate the bit. This method is not utilized because of the great difficulty in locking the air motor assembly against rotation as the drill bit cuts the bore. In view of the advantages of inhole drill assemblies, there is a need for a mechanism which will effectively prevent rotation of the motor assembly for an inhole drilling device.